docs: def sendmail_sync(
          self,
          sender: str,
          recipients: RecipientsType,
          message: Union[str, bytes],
          mail_options: Iterable[str] = None,
          rcpt_options: Iterable[str] = None,
          timeout: DefaultNumType = _default,
      ) -> SendmailResponseType:
          """
          Synchronous version of :meth:`.sendmail`. This method starts
          the event loop to connect, send the message, and disconnect.
          """
          return self._run_sync(
              self.sendmail,
              sender,
              recipients,
              message,
              mail_options=mail_options,
              rcpt_options=rcpt_options,
              timeout=timeout,
          )